Die-casting machine



DIE CASTING MACHINE 8, 1931 6 Sheets-Sheet l Filed Jan.

Feb. 27, 1934.

L. H. M'ORIN DIE CASTING MACHINE Filed Jan. 8, 1931 6 Sheets-Shegt 2ATTORNEY Feb. 27, 1934.

Feb. 27, 1934. H. MORIN I DIE CASTING MACHINE Filed Jan. 8, 1931 6Sheets-Sheet 4 Feb. 27, 1934. L. H. MORIN DIE CASTING MACHINE Filed Jan.8. 1951 6 Sheets-Sheet 5 Feb. 27, 1934. H. MORIN DIE= CASTING MACHINEFiled Jan. 8, 1931 6 Sheets-Sheei 6 4 III awuemtoz I IIIIIIIII/ 'ZWPatented Feb. '27, 1934 UNITED STATES PATENT OFFICE nm-casrme momma YorkApplication January 8, 1931. Serial No. 507,394

12 Claims.

This invention relates to that type of die-cast-' ing machines, in whichthe molten metal is forced into the die or mold by means of a pumpcomprising a stationary cylinder and a movable plunger. Such pumps formolten metal are commonly operated by means of compressed air admittedinto a cylinder the piston of which is connected with the pump plunger.This of course requires multiplication and complication of apparatus andoperating parts, for maintaining a supply of compressed air, togetherwith valve devices for controlling this supply to the pump-operatingcylinder. Also there is no ,convenient way for changing or varying thevamount of pressure which is to be applied to the molten metal in themold.

in another type of automatic die-casting machines the pump for moltenmetal has been dispensed with and the molten metal is forced into thedie or mold by means of a gaseous fluid, which most commonly andconveniently is compressed air, admitted directly into a pressurechamber forming a casting pot. This latter arrangement. while it doesaway with the pump, still has the complication of supplying andcontrolling the compressed air, together with the further objection thatthis air has more or less of an oxidizing effect upon the molten metalin the casting pot. This invention is embodied in a machine of the typewhich is directly mechanically operated from a source of power such as adriving motor, which may conveniently be an electric motor, asdistinguished from another type of die-casting machines in which all orsubstantially all of the various operating parts or working parts areoperated by means of a pressure fluid such as steam or com pressed air.

A somewhat general object of the invention is to provide an improvedmetal-forcing pump mechanism. A further and related object of theinvention is to embody such pump mechanism directly in the working partsof the machine to beoperatedby a movable operating partthereof. -Anotherobject is so to construct such pump mechanism that after forcing themolten metal into the die or mold this pumpmechanism will hold themolten metal in the filled mold under uniform pressure fora desiredinterval of time. Another object of the invention is to provide meansfor conveniently varying or changing such pressure at will. Anotherobject is to provide an improved metal-forcing pump which may be readilyoperated in carrying out the invention as a whole. A further generalobject in carrying out the invention is to provide an automatic? die- Ycylinder being provided at its lower forward end with an upwardly andforwardly extending delivery duct which leads to the mold, while aninlet port for the cylinder is provided in its lower side adjacent itsother end. This construction and arrangement of the pump cylinder notonly provides for filling the pump cylinder with molten metal taken froma considerable depth below the surface, where the metal is clean and ata suitable high temperature, but also facilitates the convenientoperation of the pump plunger by means of simplified operatingmechanism.

Since the pump itself has a positive delivery, it is obvious that werethis pump operated from a moving part of the machine in a positivemanner with a fixed length of stroke of the pump plunger then, when themold cavity became filled, the delivery movement of the pump plungerwould be stopped and the whole machine would be stalled or some part ofit broken. In carrying out the invention, means are embodied in theoperating mechanism of the pump whereby when the mold cavity becomesfilled with molten metal under a predetermined pressure, the forwardmovement of the pump plunger may cease while it still continues to holdthe molten metal in the mold under the desired predetermined pressurefor a suitable interval of time, after which the plunger is retracted,for filling the pump cylinder. For accomplishing this result, amovemerit-resisting yieldable pressure-applying device is connected intothe operating connections between a movable operating part of themachine and the pump plunger.

More particularly and desirably, a pressure relief device of thehydraulic type is employed which will. yield at a predetermined highpressure of the molten. metal against the advancing pump plunger whenthe mold becomes filled, and which thereafter; while still yielding,will maintain a substantially uniform predetermined high pressure of themolten metal in the mold. Since the pressure relief device becomesoperative only when the mold becomes filled with molten metal at apredetermined high pressure, the operation g weaned will remain the samewith substituted molds having mold cavities of different sizes, withinpractical limits, of course. In further carrying out the invention,adjusting means are provided whereby the molten metal in the filled moldmay be subjected to a greater or to a lesser amount of predetermineduniformly applied high pressure, as may be desired.

It is to be noted that the yieldable device referred to as a pressurerelief device, does not entirely release or discontinue the pressure onthemolten metal in the filled mold and pump cylinder, but it providesrelief of pressure in the sense that it limits the pressure to apredetermined maximum, which is then substantially uniformly maintainedwhile the device is yielding as the result of the delivery impulse whichis being applied to the pump plunger. Thus such device is a pressureresponsive device in control of the operation of the pump. Thisdefinition of terminology conveniently employed in the specification andthe claims is to be hereinafter kept in mind. The invention furtherincludes various features of construction and combinations of parts, aswill appear from the following description.

One embodiment of the invention which is i1.- lustrated in theaccompanying drawings will now be described, after which the inventionwill be pointed out in claims, reference now being had to the drawings,in which:

Fig. 1 is a side elevation as seen in Fig. 2 of one of the rotatable camassemblies employed in carrying out the invention;

Fig. 2 is a side elevation of the machine head or power end of anautomatic die-casting machine embodying the invention, with the movableoperating parts of the machine in the position which they occupy betweensuccessive casting operations, or when the machine is at rest;

Fig. 3 is a similar view of the furnace end of the machine, partly inlongitudinal central vertical section, Fig. 3 being a continuation ofFig. 2 from left to right, as is indicated by the vertical broken lineat the right of Fig. 2 and at the left of Fig. 3;

Fig. 4 is a view similar to Fig.3, somewhat reduced, showing the castingposition of the mov able operating parts there appearing;

Fig. 5 is a transverse substantially vertical section on the zig-zagline 5-5 of Fig. 2;

Fig. 6 is a similar view taken on the line 6-8 of Fig. 3;

Fig. 7 is a partial longitudinal section on the inclined line 7-7 ofFig. 2, slightly enlarged;

Fig. 8 is a slightly reduced transverse section on the inclined line 8-8of Fig. 3:

Fig. 9 is a vertical transverse section on the zig-zag line 9--9 of Fig.3;

Fig. 10 is a slightly enlarged partial longitudinal horizontal sectionon the zig-zag line l 31O of Fig. 3;

Fig. ll is a partial vertical transverse sectioz. on the line 11-11 ofFig. 3 and draw. to same scale as Fig. 10;

Fig. 12 is a similar section on the line 12--12 of Fig. 3.

In the die-casting machine shown in the drawings as an embodiment of theinvention. a main frame comprises a pair of similar logitudinal channels1 which are bolted to a series of transverse supporting benches shown asfive in number, comprising three similar intermediate benches 2, asimilarright-hand terminal bench 3 and a somewhat different left-handterminal bench 4, all of these benches being shown as tied together andbraced by means of a pair of longitudinal rods 5. A suitable furnace 6is firmly secured upon the channel bars 1 toward their right-hand ends,which project to the rear beyond the furnace. The furnace has a topplate '7 firmly secured thereon and which is conveniently dividedlongitudinally of the machine into two complementary parts. A removablelongitudinally oblong melting pot -8, in the upper part of the furnace6, has a top flange by which it is supported upon the inner depressedmargin of the top plate 7, with the upper front edge of this melting potslightly hollowed out and extending over the top of the furnace 6.

In the die-casting machine shown in the drawings as an embodiment of theinvention, a stationary die-supporting plate 9, closely adjacent to thefront end of the melting pot 8, is somewhat inclined from the verticalrearwardly at its upper edge so as to overhang'the upper edge of thewall of the furnace 6 and the edge of the melting pot 8. Thisdie-supporting plate 9 is firmly, although adjustably, secured in placeto the furnace top plate 7 by means of bolts 10 passing throughupstanding lugs formed on the top plate '7 and through lateral lugsformed on the die-supporting plate 9. This stationary diesupportingplate 9 is also further supported by other means as will hereinafterappear. A dieregister plate 11 is carried by the die-supporting plate 9at the forward side or. the latter and a stationary die-section 12covers this register plate 11 and is bolted to the die-supporting plate9. 'An upper pair of die-frame rods 13 and a similar but longer lowerpair of die-frame rods i i have their ends secured to the respectivecorners of the die-supporting plate 9, from which these rods extendforward at an upward inclination, as shown in the drawings (Figs. 3, 4,8 and 9).

This die-supporting plate 9 is further supported by means of anupstanding swinging link 15. This link 15 is pivotally supported at 16on a bracket 17 which is secured to the lower part of the front end wallof the furnace 6. The lower edge portion of the die-supporting plate 9at each of its lateral edges is pivoted at 18 to bearing blocks 19which, by means of screws 20, are adjustable up and down on the link 15,for raising or lowering this die-supporting plate 9. Thisswingingsupporting link 15 provides for moving the die-supporting plate 9forward away from the furnace 6 and melting pot 8 when it is desired tohave access between these parts, as will presently more clearly appear.Below its pivot 16 the swinging link 15 is provided with a tail arm 21to abut against 2. lug 22 on the bracket 17 for supporting the die plate9 when the link 15 is swung forwardly.

An outer movable die-section 23 is bolted on the rear face of an outeror forward die-carrying plate 24 which is slidable on the die-frame rods13 and 14, by means of the operating mechanism of the machine, someparts of which will be hereinafter noted. thereby to withdraw the outerdie section 23 away from the inner die section 12. as shown in Figs. 2and 3 taken together, or to close this outer die-section against theinner die-section 12, in order to form a complete die or mold, as shownin Fig. 4, in which these die sections form between them a mold-cavity25, which is provided with a gate opening 26 through the inner diesection 12. It is to be understood of course, as is well known in theart, that these die 9 shown in the drawings.

sections 12 and 23 are interchangeable with other die sections to besubstituted therefor and which may provide a die-cavity such as 25 oflarger or smaller size, according to the size of the article to be cast,and alsov in any case providing a die.- cavity which is complementary tothe configura tion or shape of the article which is to be produced bythe die-casting operation.

In carrying out the invention, a pump of the positive delivery type isprovided for taking molten metal from the melting pot 8 and filling thedie-cavity such as 25 with such molten metal under suitable pressure.This pump has a downwardly and forwardly inclined cylinder 27, the majorportion of which is immersed in or surrounded by the molten metal in themelting pot 8. This pump cylinder 2'7 is firmly and rigidly. althoughadjustably, supported upon the top plate '7 of the furnace 6 by means ofa forward pair 28 and a rear pair 29 of side arms formed on the cylinder27 in the same piece therewith.

This pump cylinder 27 may be adjusted forward or back by means of screws30 in lugs 31 on the furnace cover 7, and this cylinder 27 is firmlyheld down in place by means of screws 32, as At its lower forward endthe pump cylinder 27 has formed thereon an upward extension or neckwhich is provided with a delivery duct 33 which extends upwardly andforwardly and, in the particular construction shown, terminates at thetop'of the melting pot 3 in a forwardly directed and slightly upwardlyinclined rounded nozzle portion 34.

A casting nozzle 35 forms a forward and upwardly inclined extension fromthe upper end 34 of the cylinder duct 33. In the construc-- tion shown,this casting nozzle or discharge nozzle 35 is formed as a separatepiece, although so far as the present invention is concerned it could beformed in the same piece with the pump cylinder 27 as an integralcontinuation of the upper end 34 of the delivery duct 33. The outer orforward portion of this nozzle 35 tapers and is snugly received throughaligned forwardly tapering openings provided through the stationarydie-supporting plate 9 and its die-register plate 11. The rear end ofthis nozzle 35 is of a cup shape to fit over the rounded nozzle end 34,while the forward end of this casting nozzle 35 projects slightly fromthe die-register plate 11 and is rounded to fit into a. cup-shapedrecess in the stationary die-section 12, with the bore of this nozzle 35in alignment with the gate opening 26, and also with the inner or rearend of this bore in alignment with the upper end portion 34 of thedelivery duct 33 of the pump cylinder 2'7.

This nozzle end 35 is securely held in position by. the die-supportingplate 9 and its die-register plate 11 and is clamped at its ends betweenthe die section 12 and the nozzle end 34 of the pump cylinder neck orduct33, and accordingly does not need to be otherwise secured orattached to the nozzle end 34 of the pump cylinder- When the stationarydie-supporting plate 9 is moved forward away from the front of thefurnace '6 and melting pot 8, as hereinbefore noted, this casting nozzle35 may be readily removed for cleaning or to be replacedby a new one, asdesired. At its lower side, adjacent but somewhat removed from its openor rear end, the pump cylinder 27 is provided with an inlet port 36,through which the pump cylinder 27 may be filled with molten metal takenfrom a considerable depth below the surface, as shown in through them apivot rod or pin 46.

Figs. 3 and 4. The pump cylinder 27 has therein a pump plunger 3'7,which may be retracted to open the inlet port 36, as shown in Fig. 3,

or moved forward to force the molten metal into the die or mold to fillits cavity 25, as shown in Fig. 4. The open rear end of the pumpcylinder 27 is shown as slightly above the level of the molten metal-inthe melting pot 8.

A downwardlyand forwardly inclined plungeroperating rod 38 is inalignment with the axis of the pump cylinder 27 and is mounted forslidable operating movement through a lower forward bearing 39 which isbolted to the top of the furnace cover plate '7, and a more elevatedrear bearing 40 which is bolted upon'the upper end of a bracket arm 41which is bolted to the rear wall of the furnace 6, and which is alsoshown as provided with apair of lateral braces 42, the lower ends ofwhich may be secured to the side frame channel bars 1. The pump plunger37 and the plunger-operating rod 38 are connected together by means of areadily removable arm or coupling link 43, having at its respective endsa non-rotative detachable hook connection with the plunger 37 and itsoperating rod, 38, as shown in Figs. 3 and 4. In the position of theoperating parts shown in Fig. 3 this coupling link 43 may be removed bysimply lifting it 011?, thereby permittingthe removal of the pumpplunger 37 for cleaning or for replacement by a new plunger. It will benoted that there are no obstructions above the open top of the meltingpot 8, so that thereby the pump cylinder 27, its plunger 37 andconnecting link 43 are all readily accessible from above. i

The plunger-operating rod 38, at a point intermediate of itsbearings 39and 40,'has thereon a transversely slotted yoke or cross-head 44 whichprovides for imparting sliding pumpoperating movement to this rod 38,this crosshead 44 desirably being formed in the same piece with the rod38, as indicated in the drawings. In die-casting machines, in order tobalance the; severe strains to which some of the operating parts aresubjected, commonly many of these parts are made as virtual duplicatesat opposite sides of the machine, the two parts ofsuch a pair differingfrom one another only in the respect of being made as right-hand andlefthand. Hereinafter, both for the sake of clarity of description andalso to avoid a multiplication of reference numerals, the two members ofsuch a pair ofparts will be designated by the same a reference numeral.

A pair of bearing blocks 45 engage and are slidable in the slot of thecross-head 44, these bearing blocks having extending transversely Asubstantially vertically arranged two-armed twopart. plunger-operatingrocking lever 4'7 is pivoted at its upper end. on the pivot shaft 46,and intermediate of its length is pivoted on the opposite ends of a rod48 which forms a fulcrum pivot therefor. This pivot rod 48 passesthrough a pair of laterally spaced bearing blocks 49 which,

through which are slightly slotted in an up and down direction. Thesebearing blocks are pivoted upon the ends of a pivot pin 52 which extendstherethrough and is carried by the upper part of a two-part split clamp53 which, by means of clamp bolts 54, is adjustably clamped upon alongitudinally extending slidable push rod 55 which operates the rockinglever 47 and hence the pump plunger 37. The push rod 55 is guided forsliding movement through bearings formed in the respective frame benches2, 8 and i. This push rod 55, in the operation of the machine, ispositively slid back and forth with a uniform length of stroke by theoperating mechanism of the machine, through means which will presentlybe described.

The other or power end of the machine is provided with a machine headwhich carries the initial operating parts of the machine from which theseveral individual operating parts of the machine are operated throughsuitable connections, some of which have already been described. Theframe of the machine head comprises a pair of side plates 56 which arefirmly connected together by means of a number of transverse tie-rods57, as well as also by means of a number of stationary tie shaftsforming journals for movable operating parts, as will presently bedescribed. These side frames 56 have bolted thereto a pair of legbrackets 58 which at their lower ends are pivoted respectively upon theopposite ends of a strong cross bar 59. This cross bar 59, adjacent theinner sides of the leg brackets 58, has thereon rollers 60 through whichthe machine head is supported upon forwardly and upwardly inclinedtracks 61 which rest upon and are bolted to the frame channels 1, theupper inclined supporting surfaces of these tracks 61 being parallelwith the inclined die-frame rods 13 and 1a.

This arrangement provides for adjusting the machine head as a wholeforward and back, to-

gether with all of the parts carried thereby. In

the construction shown in the drawings, an adjusting screw 62 isthreaded through the middle of the cross bar 59, from which it extendsforwardly and has a reduced outer shouldered end portion journaled in abearing 63 which is swivelled on a pivot pin 64 carried at its ends byan upstanding bracket 65, shown as formed integrally in the same piecewith the adjacent left hand frame bench 4. The outer or forward endportions of the die-frame rods 13 and 14 are supported by the plates 56and are longitudinally adjustable relatively thereto by means ofthreaded portions on these rods engaged by nuts 66. This adjustment ofthe machine head, provided along these die-frame rods, together with theadjustment therefor provided by the adjusting screw 62, provides for theaccommodation of die sections. such as 12 and 23, of different sizes,may take up more or less space between the two die-supporting plates 9and 24. Also the adjustment provided by the adjusting screw 62 aloneprovides for moving forwardly the inner stationary die supporting plate9 in the manner hereinbefore described.

The outer die-carrying plate 24 isfurzher slidably guided by means of apair of bars 67 rigidly connected thereto to move therewith andprojecting outwardly or forwardly, where they are guided for slidingmovement through the side frame plates 56. In its sliding movement,between the open condition of the die or mold shown in Figs. 2 and 3 andthe closed condition thereof shown in Fig. i. the slidable die-carryingplate 2 is cp erated through the intermediary of linkage connections 68,pivoted thereto and to the side frame plates 56, as shown in Figs. 2 andat.

A drive link 69, virtually forming a member of the linkage system 68,carries a pivot pin 70 atits upper end by which it is pivoted to the twosimilar initial or left-hand lever-forming links of this linkage 68, asshown in Figs. 2 and 5. From this upper pivotal connection 70 this drivelink 69 extends downward and is provided longitudinally thereof in itslower end portion with a guide slot '71 by which this link is slidably,as well as pivotally, guided on aguide roller 72 journaled on the middleportion of a cam shaft '73, the outer end portions of which areiournaled in the slide frame plates 56. Above its guide slot 71 thedrive link 69 carries a stud '74, on the re spective ends of which are'journaled a pair of cam follower rollers 75.

These cam rollers 75 are engaged by suitably shaped cam grooves 716 inthe adjacent inner sides of a pair of large transversely spaced camgears 7'7 which are mounted upon the cam shaft '73 and are shown (Fig.5) as keyed thereto, although in the machine shown it is only necessaryto fix one of these cam gears upon the cam shaft, as will presently moreclearly appear. These twin cam gears '77 operate as a unit to form amovable operating part of the machine which, through the operatingconnections above noted, slides the die-carrying plate 24 back and forthfor closing and opening the die or mold, as well as also performingother functions in the operation of the machine as a whole, some ofwhich will be hereinafter noted, in the carrying out of this invention.In the machine shown in the drawings, the arrangements are such thatthese cam gears 77 are to be rotated in a clockwise or right handdirection as viewed in Fig. 2.

The cam gears 77 are rotated through the imvtermediary of a long ordouble pinion 78 which has engagement with'the gear teeth of both ofthese cam gears at the left or front end of the machine, as shown inFigure 2. This pinion 78 is journaled upon a stationary shaft 79 whichalso forms a tie-rod between the two frame plates 56. An intermediatespur gear 80, fixed on the pinion 78 at the middle of its length, isaccommodated between the margins of the spaced camgears 77. At its lowerside the intermediate gear 80 is engaged by a drive pinion 81, fixedupon a drive shaft 82, which is journaled in bearings in the side frameplates 56. At the opposite side of the machinefrom that shown in Fig. 2,and as apears in Fig. 5, this drive shaft 82 projects beyond theadjacent side frame plate 56 and at its outer end is journaled in anoutboard bearing formed in a bearing bracket 83 which is bolted to theadjaoent side frame plate 56. Adjacent its bearing in the bracket arm83, the drive shaft 82 has a drive pulley 84 loosely rotatably mountedthereon.

This drive pulley 84 may be rotated from any convenient source of power,such for example as an electric motor (not shown) which may beconveniently mounted upon the top of the machine head T fern-led by theconnected side plates 56. clutch mechanism, the details of which are notshown, is provided for clutching the drive pulley 84 to the drive shaft82 and for disconnecting it therefrom. The clutch mechanism referred tomay be manually controlled at will by means of a clutch-controllingshaft 85 which is also under the automatic control of a clutch cam 86carried by a cam holder 87 which is fixed upon the adjacent-projectingend of the 1,948,99d' cam shaft '73, which latter is rotated by the camgears 77, one of which, however, would be sumcient forthis purpose ofrotating the clutch-controlling cam 86.

The drive shaft 82 at its otheror forward end, appearing in Fig. 2, hasfixed thereon a brake drum 88. This brake drum 88 is engageable by atwo-part brake band 89. The two parts or shoes 89 of this brake band arepivotally mounted on a stud 90 carried by the adjacent frame plate 56,and these brake shoes are urged towards their braking relation with thebrake drum 88 by means of a pair of compression springs 91 on the outerends of a tension link 92. ,A brake-controlling rod 93 forms a part ofthe connections through which the above noted brake is controlled concomitantly with thecontrol of the drive clutch mechanism, in such manneras to release this brake when the drive clutch is in engagement foroperating the machine, and to apply the bralre when the drive clutch isdisengaged, for thereby quickly stopping the entire machine. Althoughthe details of the drive clutch mechanism and of the controllingmechanism therefor and for the brake are not all shown in the drawings,it might -be noted that the arrangement is such that the machineautomatically stops at the end of each complete cycle, or the machinemay be caused to operate continuously if so desired, and also themachine may be stopped, together with the appli cation of the brake, atany intermediate point desired, in its cycle of operation.

At a suitable distanceinward or towards the right from its bearing inthe left-hand end frame bench 4, the slidable plunger-operating push rod55 has bolted thereon a block 94 which at its sides is provided withtrunnions 95 on which are pivoted the ends of a pair of operating links96 which extend substantially horizontally outward towards the left(Fig. 2) where their ends are more widely separated, as more clearlyappears in Fig. 5. These ends of the operating links 96 are pivotedrespectively on pivot studs 97 which are carried by the lower ends ofthe two parts of a substantially vertically disposed two-part or doubleoperating lever 98. At an intermediate point of its length the two partsof the operating lever 98 are pivoted on a stationary cross shaft 99which also serves to tie together the lower edge portions of the sideframe plates 56. The upper ends of these two parts of the operatinglever are provided with inwardly projecting studs 100 on the inner endsof which cam follower rollers 101 are journaled. These cam rollers 101are engaged in suitably shaped cam grooves 102 provided on the outersides of the large cam gears 77.

In the particular construction shown, these cam grooves 102 are notformed directly in the body of the cam gears 77, with their cam walls inthe same piece therewith. In the construction shown, the inwardlydirected .outer wall of the cam groove 102 is formed by an outer camring. 103 which is firmly secured in place on the outer side of the camgear 77 by means of a series of rivets 104, as shown in Fig. 1. Theoutwardly directed inner cam wall of the cam groove 102 is formed inpart by means of a ring or collar 105 on the cam shaft 73 and in part bymeans of an inner cam member 106 fitting partly around the collar 105,and projecting therefrom. This inner cam member 106 is firmly anchoredto the cam gear 77 by means of an interposed key 107 and -is secured inplace on this cam gear by means of'a pair of screws 108, as shown inFig. 1. As the cam gears 77 are rotated their cam grooves 102 will rockthe operating lever 98, thereby to operate the pump plunger 37 throughthe operating con= nections which have been described. tour andrelationship of the cam grooves 76 and 102 provided by the cam gears '77are of course such as to operate the pump plunger 37 in proper timedsequence with the operation of the other parts of the machine, includingthe slidable die carrying plate 2%.

It might here be noted that when the machine head, including the sideframe plates 56, is to be adjusted forward or back longitudinally of themachine, as hereinbefore described, and there fore carrying with it thecam operated rocking lever 98 which operates the push rod 55, such adjustrnent is provided for by the hereinbefore described adjustable clamp53, through which the rocking plunger-operating lever 47 connected tothe push rod 55.

In carrying out the invention and as an impor= tant feature thereof, amovement-resisting yield able device is connected into the abovedescribed operating connections, from the cam gears 77 to the pumpplunger 37, for operating thelatter, such device being adapted to yieldunder a predeterminedmaximum pressure of molten metal against theplunger 37 after the mold-cavity 25 has become filled, whereby the pumpplunger 3'7! may stop its forward delivery movement while stillcontinuing, for a predetermined interval of time. to apply a desiredpredetermined pressure to the molten metal in the filled mold. Thisfeature of the invention is carried out by means of a hydraulic pressurerelief device which, dur ingthe time in which. it is yielding, willapply a substantially uniform delivery impulse to the pump plunger 37,thereby correspondingly maintaining a predetermined substantiallyuniform pressure of the molten metal in the filled mold.

In the construction shown in the drawings, the bearing blocks i9 whichcarry the fulcrum pivot rod 48 forthe plunger-operating lever 47 aremovably mounted to yield backwardly towards the right (Figs. 3 and 4)during the terminal portion of the delivery impulse imparted to the pumpplunger 37, and these bearing blocks 49 be ing returned to theiroriginal forward position when the pump plunger 37 is drawn back orretracted. These bearing blocks 49 are guided for horizontal slidingmovement in guide slots 109 formed in the laterally spaced side platesof a supporting frame 110 which at its forward end is bolted to the rearwall of the furnace 6, and which at its other or rear end has a cylinderhead 111 shown as formed in the same piece therewith.

The cylinder head 111 forms a part of a liquidcontaining-pressure reliefcylinder having 9. cylinder body 112 provided with feet 113 bolted downupon a base plate 114 which is bolted to the top of the right hand endframe bench 3. This cyl-' inderbody 112 and its forward or left-handhead 111 are hermetically sealed and firmly secured together by means ofa series of screw studs 115. An outer orrear cylinder head 116 issimilarly firmly and hermetically secured to the other end of thecylinder body 112' by means of a ser.es of screw studs 117. A pressurerelief piston 118 is/contained within the cylinder body 112 and the,

is pivotally I at Milli wit H ll) nected to this fulcrum rod 48 throughthe intermediary of a coupling block 121, the fulcrum pivot red 48passing through this coupling block, which fills the space between thetwo slidable bearing blocks 49, and the piston rod 119 having a reducedshouldered end portion passing through this coupling block 121 andfirmly secured thereto by means of a terminal nut 122. It will now beobvious that the fulcrum pivot 48 of the plunger-operating lever 4'7cannot move without also moving the pressure relief piston 118 in theclosed and hermetically sealed cylinder body 112. I

A piston guide rod 123 has its inner or lefthand end firmly and rigidlysecured to the inner or right-hand end of the piston rod 119, such as bymeans including a telescopic relation (indicated in Fig. 10) of the endportions .of these two rods, so that thereby this piston guide rod 123forms a rigid continuation of the piston rod 119. This piston guide rod123 passes out through the rear cylinder head 116. to which it ishermetically sealed by means of an outer packing gland 124 and alsofurther sealed at the inner side by means of a packing device 125. Thepiston 118 is shown as recessed in step fashion on its inner orright-hand side, and adjacent to its hub boss, by which it is secured onthe piston shaft 119, this piston has provided through it a circularseries of openings or holes 126 a shown in Figs. 10 and 12.

These openings 126 are controlled, to be closed or opened, by means of aone-way valve or check valve 127, shown as in the form or a steppedvalve head which is slidable inwardly or to the right on the inner endportion of the piston rod 119 in order to open the apertures 126 throughthe piston 118. This one-way valve 127 is urged towards its seat on thepiston 118 by a coiled spring 128 which is backed up by an abutmentwasher 129 held on the inner reduced end portion of the piston rod 119and abutting against a shoulder formed by the inner end of the pistonguide rod 123, as shown more particularly in Fig. 10. This check valve127 permits the piston 118 to be freely retracted in the cylinder 112towards its cylinder head 111, or towards the left as shown in Figs. 3,4 and 10, but prevents this piston from moving in the opposite directionso far as this valve is concerned.

The wall of the cylinder body 112 is cored out to provide longitudinallytherein rather large passages 130, shown as four in number, whichcommunicate through transverse radial notches 131 with the interior boreof the cylinder body 112 immediately adjacent to its forward cylin-,

der head 111. The other ends of these passages 130 communicate throughports 132 in the other cylinder head 116 with a cavity 133 cored outtherein, as shown in the drawings. A single passage or bore 134 in thecylinder head 116 com nects the interior of the cylinder 112 with thecylinder head cavity 133, in which this bore 134 forms a valve seat. Itwill be noted that this valve port 134, together with the abovedescribed passages, forms a by-pass from one end of the cylinderbody'112 to the other, aroundthe piston 11.8.

The valve port 134 is normally closed by means of a seated poppet valve135 in the cylinder head cavity 133 and having an outwardly projectingvalve stem 136 which is guided in a valve cage or tubular plug 137,relative to which this valve stem is sealed by means of an outervpacking gland 138. For accommodating the valvelcage.

137. the upper portion of the cylinder head 116 is provided with aprojecting boss 139 having.

through it a large bore 140 which extends into the cylinder head cavity133 in alignment with the valve port 134, which together with this bore140 are shown as inclined downwardly in an inward direction.

The valve cage 137 is screw-threaded into the outer end portion of thisbore 140 and also is provided with packing by which it is sealedtherein, as shown in the drawings. The inner end portion of the valvecage 137 is reduced to provide a shoulder and a rather strong coiledthrust spring 141, surrounding this reduced portion of the valve cage137, abuts against its shoulder and at its other or inner end bearsagainst the valve head 135, normally holding the latter seated, forthereby closing the by-pass formed by the valve port 134. The tension orstrength of this valve-closing spring 141, and therefore the amount ofresistance which it offers against being unseated to open the valve port134, may be adjusted by screwing the valve cage 137 inwardly forstrengthening the spring and outward for weakening it.

Normally, that is, for use, the closed cylinder 112, together with theabove described passages and cavities, is filled with a suitable oil,which for clarity of illustration is not shown in the drawings. For thusfilling the cylinder it is provided at its top with an opening 142 intothe adjacent passage 130. This filling opening 142 may be kept closed bymeans of an ordinary screw-plug if so desired, but for convenience inkeeping this cylinder filled, this filling opening 142 is shown in thedrawings as having con nected thereto an upstanding filling pipe 143leading from an oil tank 144 and provided with a valve 145 of theordinary stop-cock variety. which of course' is kept closed exceptingwhen the pressure relief cylinder 112 is to be filled.

In its lower portion the outer or rear cylinder head 116 has a solidwallportion 146 which bridges the cylinder head cavity 133 and hasprovided through it a downwardly and outwardly inclined bore 147 leadingfrom the lower part of the inside of the cylinder 112. A short pipesection 148 is screwed into the outer end of this bore 147. The outerend of this pipe section 148 carries a removable union or connector 149for the removable attachment thereto of a small pipe or tube 150 whichleads to a pressure gage, which is not shown but may be of ordinaryconstruction and which enables the attendant of the machine at any timeto note the pressure which is being applied to the oil in the cylinder112 during the operation of the machine. Also, by disconnecting thepressure gage tube 150, the pipe section 148 may be utilized fordraining the oil from the cylinder 112 when it is desired to renew suchoil. Also, if desired, there may be pro vided at the top of the cylinder112, for example in the upper portion of the outer cylinder head ,116, asmall normally pluggedair-escape orifice (not shown), for moreconveniently. filling the cylinder with oil.

mold-cavity, such as 25, thus becomes filled, the

the rotating cam gears 77 are still imparting a delivery impulse to thepump plunger 37 through the hereinbefore described operatingconnections. The result, in'the operation of the invention, is that thefulcrum pivot rod 48 for the plungeroperating lever 47 is forcedbackward or towards the right as viewed in Figs. 3, 4 and 10, carryingwith it the pressure relief piston 118. The pressure applied by thepiston 118 to the oil contained in the cylinder 112, when such pressurehas reached a desired predetermined maximum, pushes open the pressurerelief valve 135 againstthe resistance of itsclosing spring 141 andopens a restricted by-pass between this spring-pressed valve 135 and itsseat on the valve port 134, thereby establishing a by-pass around thepiston 118 from the right hand end to the left hand-end of the cylinder112.

Since the valve 135 does not open except under the desired predeterminedhigh pressure, this valve remains closed for holding the piston 118stationary, with the fulcrum pivot rod as correspondingly stationary,against movement during the first stage of the complete operation whilethe mold-cavity 25 isbeing filled with the molten metal under thedesired pressure. This pressure to be applied to the molten metal in themoldcavity 25 is regulated or determined by the above describedadjustment of the valve-closing spring 141, which also similarlydetermines the size and thus the capacity of the restricted by-passwhich this valve 135 provides when the valve-closing resistance of thespring 141 is overcome and this valve 135then permitted to open more orless, that is,- to a greater or less extent depending upon the adjustedstrength of the valve spring 141.

It has been found in practice that when the by-pass valve 135 is thusforced open it will thereafter provide a substantially uniformresistance to the flow of .oil by which the backward movement of thepiston 118 is permitted to take place, and therefore will cause the pumpplunger 37 to apply a correspondingly uniform pressure to the moltenmetal in the pump cylinder 27 and die-cavity 25, this pressure beingcontinued for adesired interval of time while the casting in themold-cavity 25 is hardening, preparatory to the opening of the mold andthe ejection of the casting by means of suitable ejector mechanism (notshown).

As soon as the pump-operating push rod 55 reaches the limit of itsbackward movement, which is towards the right as viewed in Figs. 2, 3and 4, and begins to be retracted in the opposite direction, thenimmediately the pressure of the pump-plunger 37 on the molten metal inthe pump cylinder 27 and die-cavity 25 will be released, that is,discontinued. In Fig. 4 of the drawings this pump-operating push rod 55is shown at the limit of its movement towards the right, the pumpplunger 37 having been previously stopped by the molten metal in thefilled mold, while the pressure relief piston.l18 has already yieldedbackwardly to the full extent required, and the pressure relief valve135 accordingly has already again closed, preparatory to the opposite orretractive movement of all oi. these'connected parts.

A back stop ring 151, desirably formed of suitable fibre, surrounds theslidable bperating rod 38 for the. pump plunger 37 between the crosshead44 and the rear bearing 40, being shown as. adjacent to the latter. Thisback stop. 151 prevents the possibility of overthrow movement of thepump plunger 37 when it is retracted and also assures that the pressurerelief piston 118 will be fully retracted towards the cylinder head 111.Even should the piston apertures 126 and open check valve 127 offer someresistance to the retractive movement of the pressure relief piston 118,that will have no effect whatever upon the operation, since all of theinterconnected operating parts from the pump plunger 37 to the .camgears 77 arepositively moved in this ne tractive movement, by the cams102 carried by these cam gears 77.

The inner cam members 106 on the cam gears 77 may be convenientlyremovedand replmed through large openings 152 provided through the side frameplates 56, as shown in Fig. 2. Also it maybe noted that the leading ordriving face of this cam member 106 may be cut away to a different shapeif desired, for example it may be so shaped as to start the deliverymovement of the pump plunger more slowly, and then to impart a graduallyaccelerated delivery movement there-= to.

It is obvious that various modifications may be made in the constructionshown in the drawings and above particularly described, within theprinciple and scope of the invention as defined in the appended claims.

I claim:

1. In a die-casting machine, the combination of a positive delivery pumpfor forcing molten metal into a mold to fill the latter, a movableoperating part of the machine, connections between the said part and themovable member of the pump for operating the latter, and a hydraulicpressure relief device embodied in the said connections and responsiveto a predetermined maximum pressure of molten metal on the movablemember of the pump to stop the delivery movement of the latter.

2. ma die-casting machine, the combination of a positive delivery pumpfor forcing molten metal into a mold to fill the latter, a movable,operating part of the machine, connections between the said part andthe movable member of the pump for operating the latter, and a hydraulic7 pressure relief device embodied in the said connections and responsiveto a predetermined maximum pressure of molten metal on the movablemember of the pump to stop the delivery movement of the latter, andafter the said movable member has stopped the said device being adaptedto apply thereto through the said connections a substantially uniformdelivery impulse for a desired length of time for therebycorrespondingly maintaining a predetermined substantially uniformpressure of the molten metal in the filled mold.-

3. In a die-casting machine, the combination of a positive delivery pumpfor forcing molten metal into a mold to fill the latter, a movableoperating part of the machine, connections between the said part and themovable member of the pump for operating the latter, a hydraulicpressure relief device embodied in the said con- ,ingly maintaining apredetermined substantially uniform pressure of the molten metal in thefilled mold, and adjusting means embodied in the-said hydraulic devicefor rendering it responsive to a selected maximum pressure of moltenmetal in the pump and the filled mold and for then pre venting furtherincrease in the said pressure.

4. In a die-casting machine, the combination of a cylinder for moltenmetal provided with an eduction passage leading to a mold, a plunger inthe cylinder for forcing molten metal from the cylinder into the mold tofill the latter under pressure, a movable operating part of the machine,connections between the said part and the plunger to reciprocate thelatter, a rocking lever included in the said connections, a yieldablymovable fulcrum pivot for the said lever, a stationary liquidcontainingcylinder, a piston in the latter cylinder, a connection between the saidfulcrum pivot and the said piston by which movement of the fulcrum pivotwill move the piston, a normally closed pressure relief v lve in controlof the movement of the piston during the delivery stroke of theplungerto open at a predetermined maximum pressure and thereafter tomaintain a uniformly restricted by-pass between the opposite ends of thepiston so that thereby the delivery movement of the plunger may stop andthe fulcrum pivot of the said lever may yield under the control of thepressure relief valve, and a freely opening check valve to permit thefree return of the piston by the said lever in the reverse movement ofthe latter which retracts the plunger.

5. In a die-casting machine, the combination of a cylinder for moltenmetal provided with an eduction passage leading to a mold, a plunger inthe cylinder for forcing molten metal from the cylinder into the mold tofill the latter under pressure, a movable operating part of the machine,connections between the: said part and the plunger to reciprocate thelatter, a rocking lever included in the said connections, 7 a yieldinglymovable fulcrum pivot for the said lever, a stationary liquid-containingcylinder, a piston in the latter cylinder, a connection between the saidfulcrum pivot and the said piston by which movement of the fulcrum pivotwill move the piston, a by-pass being provided by the cylinder aroundthe piston, a normally closed yieldable valve in control of the by-pass,a spring for holding the said valve closed with the piston stationaryuntil the liquid in the cylinder reaches a predetermined highpressure inthe delivery movement of the plunger, whereupon the valve openssufficiently to permit the piston to move under a substantially uniformresistance which causes the plunger to apply a substantially uniformpressure to the molten 'metalin the pump cylinder and mold, means foradjusting the valve-closing spring for thereby varying the uniformlyapplied pressure of the pump plunger on the molten metal, and a one-wayvalve to permit free return movement of the piston when the pump plungeris retracted by the reverse movement of the said lever.

6. In a die-casting machine, the combination of a melting pot, adownwardlyand forwardly inclined cylinder in the melting pot provided atits lower forward end with an upwardly and forwardly extending ductleading to a mold and, provided at its lower side adjacent its other ending lever having upper and lower lever arms of which the upper arm isconnected to the said slidable rod for operating the plunger, a movableoperating part of the machine, connections between the said part and thelower arm of the said lever for rockingthe latter back and forth at theproper time, a transversely movable fulcrum pivot for the said rockinglever, a piston connected to the said pivot to be moved thereby, aliquid-containing cylinder for the piston, a

.normally closed pressure relief valve for opening a restricted by-passaround the piston only at a predetermined high pressure in the deliverystroke of the plunger, and a freely opening check valve to permitunobstructed return movement of the piston and lever and plunger.

7. In a die-casting machine, the combination of a melting'pot, a rigidlysupported downwardly and forwardly inclined cylinder in the melting pothaving a duct leading from its lower forward end to a mold for fillingthe latter with molten metal from the cylinder and having an inlet portin its lower side adjacent its other end, a plunger in the cylinder, adownwardly and forwardly inclined plunger-operating rod connected to theplunger, a substantially vertically extending two-armed lever having itsupper arm connected to the said slidable rod, a. slidable push rodextending longitudinally of the machine and connected to the lower endof the said lever, a substantially vertically extending two-armedoperating lever having its lower end connected to the push rod forsliding the latterback and forth thereby to operate the pump plunger, arotatable part of the machine having an operating cam in engagement withthe upper end of the said operating lever, a transversely slidablefulcrum pivot for the said plunger-operating lever,

a stationarily mounted liquid-containing cylinder, a piston in thelatter cylinder connected to the said fulcrum pivot to be moved thereby,a normally closed adjustable pressure relief valve in control ofa-by-pass in the cylinder around the piston arranged to permit movementof the piston only at a selected predetermined high pressure of themolten metal against the pump plunger, and a freely opening by-passvalve through the piston to permit free return movement of the pistonand the operating lever and the pump plunger.

8. In a die-casting machine, the combination of a melting pot, a rigidlysupported cylinder for molten metal in the melting pot inclineddownwardly and forwardly and having at its lower forward end an upwardlyand forwardly extending duct for conveying molten metal from thecylinder into a mold to fill the latter and having an inlet port in itslower side adjacent its open rear end, a plunger in the cylinder, andmeans for operating the plunger to impart a delivery stroke thereto forfilling the mold followed by a return stroke in which the said inletport is uncovered for filling the cylinder from the melting.

9. In adie-casting machine, the combination of a melting pot, a rigidlysupported downwardly and forwardly inclined cylinder in the melting pothaving a duct leading from its lower forward nected to the said slidablerod, a slidable push rod extending longitudinally of the machine andconnected to the lower end of the said lever, a substantially verticallyextending two-armed operating lever having its lower end connected tothe push rod for sliding the latter back and forth thereby tooperate'the pump plunger, a rotatable part of the machine having anoperating cam in engagement with the upper endof the said operatinglever, a transversely movable fulcrum pivot for the saidplunger-operating lever, and a yieldable device connected to the saidmovable pivot adapted to yield only under a predetermined maximumpressure of molten metal against the advancing plunger of the pump.

10. In a die-casting machine, the combination of a pump cylinder formolten metal having a delivery duct leading to a mold, a plunger in'thecylinder for forcing the molten metal from the cylinder into the mold tofill the latter, and op erating mechanism for the pump plunger includinga movable part of the machine and such mechanism further including a.yieldable device connected therein to yield only under a predeterminedhigh pressure of the molten metal against the advancing plunger, thesaid yieldable device comprising a. liquid-containing cylinder, a pistonin the latter cylinder, a normally closed pressure relief valve foropening a. restricted by-pass around'the piston only at a predeterminedhigh pressure in the delivery stroke of the pump plunger, a spring forholding this relief valve closed until such high pressure is reached,means for adjusting the valve-closing spring for thereby varying thepressure of the pump plunger on themolten metal in the filled mold, anda one-way valve to permit free return movement of the piston and thepump plunger when the latter is to be retracted by its said operatingmechanism. I

11. In a die-casting machine, the combination of a cylinder for materialto be cast provided with an eduction passage leading to a mold, aplunger in the cylinder for forcing said material from the cylinder intothe mold to flll the latter under pressure, a movable operating part ofthe ma chine, connections between the said part and the plunger toreciprocate the latter, a rocking. lever included in the saidconnections, a fulcrum pivot for said lever, and a yieldable devicesupporting the pivot and adapted to yield only under a predeterminedmaximum pressure of said material against the advancing plunger of thepump.

12. In a die-casting machine, the combination of a cylinder for materialto be cast provided with an eduction passage leading to a mold, a.

plunger in the cylinder for forcing said material from the cylinder intothe mold to fill the latter under pressure, a movable operating part ofthe machine, connections between the said part and the plunger toreciprocate the latter, a rockinglever included in the said connections,a fulcrum pivot for said lever, a yieldable device forming a mountingfor said pivot and adapted to yield onlyunder a predetermined maximumpressure of said material against the advancing plunger of the pump, andadjusting means embodied in the said device for rendering it responsiveto a selected maximum pressure of said material in the pump and filledmold and for then preventing further increase in the said pressure.

' LOUIS n. MORIN.

